Release Date

Dec 10, 2019

This version uses the Arnold core. 




The following important changes were done as a part of MtoA 4.0.0. You can find more information about them here.

Autodesk Network Licensing now requires new license files with an updated 2020 version. Please follow the instructions on this page to generate your license file. More info about Arnold 6 licensing can be found here.

The default installation directory of Mtoa has been modified from this version to be installed within the Autodesk directory. Users will still have full control over installing to any directory of their choice. For example : Linux - /usr/autodesk/arnold Osx : /Applications/Autodesk/Arnold and Windows C:/Program Files/Autodesk/Arnold/


MtoA 4.0.1 is a feature release, that is binary compatible with 4.0.* versions. It includes the following improvements:


MaterialX shader: This adds a way for users to be able to assign a material encapsulated within a materialX file directly no the shape.

New aov_write_vector shader: This enables the writing of vector values into a vector typed AOV, for example for recording positional values. These would previously have been clamped when using rgb typed AOVs.

Progressive rendering improvements: Performance and memory consumption in progressive rendering mode has been improved in some render setups. These improvements currently require all outputs to either use box or closest filtering and is not compatible with deep drivers. The expected performance and memory improvement should be roughly proportional to your AA settings. (#9094)

Improvements to Import Arnold Shaders: The Import Arnold shaders workflow now also supports MaterialX (mtlx) files allowing users to import the file as a maya shading graph. Improvements have also been made to support more attribute connection types.

Incompatible Changes

OSX minimum version is now 10.11: We have raised the minimum version required for OSX from 10.9 to 10.11.


#3906MacOS - Maya crashes with docked ARV and switching Viewport to Arnold
#4049Cannot run kick on macOS
#3122Light linking doesn't work with XGen
#4052Maya triplanar projection node renders incorrectly
#4060Changing cameras in Arnold Viewport is not triggering a re-render.
#4064Adding second aiAxfShader to objects the AxF Filename and Texture Path is blank.
#2876Attributes added to a set go under Arnold > Extra Attributes
#3494MtoA - User added attributes appear under the Arnold tab, should be in Extra Attributes.
#3834'Isolate Select' crashes when a shading node is deleted
#3873Saving an image with a .mb extension crashes MtoA
#3879Saving an image with the extension .hdr crashes MtoA
#3950Arnold Render View crashes when isolate selecting bifShapes
#3973deepexr crash when editing scene and Save Final Image enabled in ARV
#4016Import materialx files as maya shading nodes
#4031aiAfxShader does not appear in Hypershade node <tab> add node search.
#4036AxF: failed to export error when adding AxF shader
#4037AxF: no texture path provided error
#40413D Manipulation capability in Arnold RVW has regressed
#4042error with monochrome 8bit images processed to .tx
#4044Set 8bit compression to dwaa
#4048aiMotionVector custom AOV crash when merging_geometries
#4051[ARV] Test resolution scales the image buffer
#4053'Solid Angle' is still mentioned in the Help menu
#4059Arnold crashes while making graph changes while bifShape was isolate selected in RVW
#4062make licensing manager launch asynchronously
#4065export radius_attribute fro alembics on aiStandIn
#4066GPU Cache prepopulation error
#3966template file navigation not intuitive
#4008-seq does not work with arnoldRender command
#4015[Import Arnold Shaders ] : Support connection where data types are not the same
#4020Create MaterialX shader Node
#4024export aiLookSwitch to include_graph / MaterialX
#4033Export / Import shaders should support shading groups
#4056add aov_write_vector shader
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